Container associable with airless pumps and method for its production

ABSTRACT

A container comprising a rigid body ( 5 ) having a neck ( 6 ) defining an aperture providing access to the container cavity and a bag ( 9 ) positioned in the interior of the body ( 5 ), the bag being formed of thermoplastic material and itself having a neck ( 2 ) from which there radially extends a flange ( 3 ) which rests on a free edge of the neck ( 6 ) of the body ( 5 ) and defines a hole for providing access to the cavity of the bag ( 9 ) and for sealedly housing the body of a hermetic pump (P) operable manually to withdraw the fluid substance (F) from the bag and feed it to the outside through its dispensing stem (S), the bag being formed by hot blow moulding of a preform placed directly within the container, said bag having a substantially uniform thickness and being detached from the container along its entire outer surface.

The present invention relates to a container associable with a manuallyoperable pump for dispensing fluid substances contained under airtightconditions in a deformable bag housed in a rigid body.

It is known to enclose fluid substances (both liquid and creamy) incontainers from which these substances are dispensed by manuallyoperating a small pump mounted on the mouth of a respective container.to Pump operation causes a quantity of fluid substance to be withdrawnfrom the container in which—if the container is rigid—a vacuum formswhich would prevent further substance withdrawal and dispensing if airwere not allowed to enter the container (which generally takes place inthose regions in which the pump makes contact with and slides on thepump body), or if the container did not comprise a base sealedly movablealong an internal cylindrical surface of the container (see for exampleU.S. Pat. No. 4,691,847, U.S. Pat. No. 4,694,977 and U.S. Pat. No.5,971,224): this latter system for compensating the container volume byreducing its internal volume while maintaining the internal pressureconstant is however very laborious and costly.

In many cases it is opportune or necessary that the fluid substance tobe dispensed by a pump never comes into contact with the atmosphereinside the container (with the dispensing pump mounted on it): sealingthe fluid out of contact with the atmosphere is important if thecomposition of the fluid within the container is not to undergoalteration, or if it is essential that the fluid substance enclosed inthe container remains sterile. To achieve this, U.S. Pat. No. 3,420,413has proposed a device comprising a bag containing the fluid substancewhich is to remain isolated (from the atmosphere) inside the bag which(see column 4, lines 22-28) is made of elastically deformable flexiblematerial and has a neck on which a support element (having a profiledaperture for housing a pump) is sealedly applied after the bag has beenfilled with the fluid substance to be dispensed: after this, a pump issealedly mounted on said support element to hence prevent contaminationof the fluid substance by the air (column 5, lines 15-38). The bagcontaining the fluid substance and having the pump sealedly mounted onits neck is then inserted into a rigid body (obviously being verycareful that the free end of the rigid body does not come into contactwith the bag filled with fluid substance, in order not to break it) onwhich said support element is then positioned and fixed (column 5, lines56-61). Hence between the outer surface of the bag and the inner surfaceof the rigid body an interspace is formed which is connected toatmosphere via a hole provided in the container base; in this manner,when the fluid substance is withdrawn from the bag by operating thepump, the bag is squeezed by the atmospheric pressure so that thesubstance can be easily withdrawn and expelled to the outside by thepump (column 5, lines 70-73). The main drawback of the aforesaid deviceis that the deformable bag must be filled with fluid substance beforethe bag is inserted into the respective rigid container and that theoperation involved in inserting the bag into the container is verydelicate because the bag can be easily torn while being inserted intothe container interior.

JP 05 031790A and JP 05 031791A published on Sep. 2, 1993 describe how abag of elastically deformable material can be produced directly within arigid container. For this purpose an elongated preform (made ofthermoplastic material and having an elongated hollow cylindrical body,open at one end where the preform presents a neck from which a flangeradially projects) is inserted into a rigid container having a mouthfrom which a neck extends, on the free edge of which there rests theflange of the preform, which is heated, thrust towards the containerbase by a pusher and then inflated within the container, until a bagforms, the outer surface of which adheres (at least for a large part ofits surface) to the inner surface of the container. The bag obtained inthis manner also has a neck, at least an end portion of which presentsoutwardly projecting longitudinal ribs, with some radial ribs orprojections projecting from that surface of the preform flange whichfaces the free edge of the neck of the container in which the bag isinserted: these ribs or projections define passages for the air whichpenetrates from the outside between the container and bag to enable thislatter to flatten or inwardly deform during outward dispensing of thefluid substance through the pump, so preventing the formation inside thebag of a vacuum which would prevent dispensing of the fluid substance.

In particular, in the two Japanese patents the method used to inflatethe bag within the container imposes considerable stresses on the bagwhich can break it both during inflation and during use.

This is substantially due both due to the fact that the productionmethod causes the bag to adhere at least in some points to that part ofthe cavity within which it is inflated, and to the fact that the initialstretching caused by the pusher creates non-uniformity in the finalthickness of the bag walls which are thinner in the top lateral regionthan in proximity to the base and in the base itself.

A further problem of the known art is that by inflating the bag by theaforedescribed system it is not possible to completely fill the cavity.In other words, container regions remain in which the bag is verydetached from the wall defining the cavity. This occurs not only inthose positions “difficult” to fill by inflation, for example close tocorners, but also in regions pertaining or close to the container walls.This is due to the presence of air pockets which remain trapped withinthe interspace between the bag and cavity during inflation.

The main object of the present invention is therefore to provide adevice of the stated type in which the respective deformable bag is lesssubject to breakage and perfectly occupies the entire volume of thecavity within which it is inflated.

As the device described herein is preferably usable to contain anddispense valuable products (such as perfumes, creams, deodorantsubstances, medical substances and the like) for which transparentcontainers, for example of glass, are used, the fact that neither airpockets nor portions in which the bag is much more detached from thecavity walls than in other portions can be seen is extremely importantfrom the aesthetic viewpoint.

Moreover the aforedescribed system cannot be controlled, hence the airpockets are variable and consequently the bag volume varies at anyparticular time, so that a constant capacity cannot be guaranteed.

These and other objects are attained by a device in accordance with thetechnical teachings of the accompanying claims.

The ensuing description provides a non-exclusive embodiment of thedevice which is indicated by way of non-limiting example; it isrepresented with the aid of the accompanying drawings, in which:

FIGS. from 1 to 7 represent in section the various steps in the processby which the container is produced; and

FIG. 8 and FIG. 9 show respectively an enlarged detail of FIGS. 6 and 7.

Reference will firstly be made to FIG. 1 which represents a first stepof the method of the present invention.

Initially an external rigid body 5 is provided having a neck 6 definingan aperture giving access to the body cavity 7. The neck preferablypresents an external thread 6A used to screw down a hermetic pump (bymeans of a ring cap) as described hereinafter.

The body 6 is formed preferably of transparent material, such astransparent plastic or glass.

A preform 8 is provided, formed by moulding a plastic material, such asPE, PET, PP or the like, or by co-injection moulding various layers ofmutually different materials. The preform 8 comprises a lowerly roundedelongated body. It also comprises a neck 2 from which a flange 3radially extends. Teeth (not shown), the use of which is clarifiedhereinafter, extend from the outer part of the neck.

The transverse body dimensions of the preform 8 are such that it can befreely inserted into the rigid body 5, while the preform neck 2 isprofiled and has dimensions such that it easily penetrates into the holein the neck 6 of the body 5, with the free ends of the teeth beingsubstantially in contact with the inner surface of the hole in the neck6, and the projecting flange 3 of the preform resting on the end of theneck 6 but without sealedly adhering to it because spaced-apart radialribs or projections (also not shown) project from the lower surface(with respect to FIG. 1) of the flange 3.

In this manner, free passages form between the flange 3 of the preformneck and the end edge of the container neck 6, whereas other freepassages also form (between each tooth 4 and the tooth adjacent to it)between the outer surface of the preform neck 2 and the inner surface ofthe hole in the neck 6 of the rigid body 5.

Essentially, the chamber 7 is in free communication with the outside.The preform is heated to a temperature sufficient to soften (plasticize)the plastic material forming the preform. In the present method it isheated, by way of example, to a temperature of 120° C. for a timebetween 4 and 7 is seconds.

Once heated, it is inserted into the body 5 to hence obtain a situationsuch as that of FIG. 1. Specifically, the preform flange 3 rests on theedge of the neck 6 of the body 5. As can be seen from the figure, anozzle 20 is inserted into the preform and is sealedly connected to theneck 2 of the preform 8. The sealed connection is made in known manner.

A first air jet is then fed into the preform to inflate the preform 8such as to form a bag 8 (indicated by the same reference numeral as thepreform) which at least partially occupies said body cavity. Theinflating air or fluid fed into the preform interior has a pressurebetween 2 and 6 bar depending on the preform thickness, preferably 3bar. The air jet feed into the preform lasts for about 0.5-1 second. Thejet air is at ambient temperature, but can also be hotter depending onrequirements.

Specifically, feeding air into the preform causes the bag to inflate sothat it adheres to the walls defining the cavity 7. The bag swells untilthe pressure of the air trapped within the interspace which formsbetween the bag and the walls of the cavity 7 reaches a value equal tothe pressure of the air fed into the preform. In this respect, thesudden adhesion of the newly formed bag against the sides of the cavity7, in proximity to the aperture, creates a seal which prevents the airpresent in this interspace from escaping. The inflation of the bag ishence only partial.

In the known art the bag is maintained under pressure while the airpresent in the interspace is allowed to seep from some part towards thecontainer neck, much higher inflation pressures being used to accelerateair seepage.

In contrast, according to the present invention, the initial air jet isinterrupted to nullify (i.e. by making it equal to the externalpressure) the pressure within the bag. The compressed air present in theinterspace 7A hence squashes the bag to separate it from the wallsdefining the cavity, and seeps upwards to emerge from the neck.

This procedure causes the bag to substantially separate from thecontainer inner walls. Essentially, any hypothetical adhesion betweenthe is bag and the walls defining the cavity, due for example to thetemperature of the plastic material and to a sort of “gluing effect”, isprevented. It should be noted that such an at least partial adhesionwould have been not only possible but indeed probable, and damaging tothe integrity of the bag.

After the time required to squash the bag and for the air to escape fromthe interspace 7A has passed (about 0.3-3 seconds, but preferably 0.5-1second), a further air jet is fed into the bag (FIG. 4).

This time the bag 8 fills the cavity 7 to a greater extent (FIG. 4). Inthis respect, the air remained trapped within the interspace 7A has aninitial volume less than that present between the preform and the cavitywalls during the preceding step. This is because at the moment the airjet is fed (FIG. 3), the bag occupies a greater cavity volume than thepreform.

As in the previous case, this further air jet is maintained for a timebetween 0.5 and 1 second. It is then halted, the bag is deflated, thecompressed air present in the interspace 7A escapes upwards, and thecondition of FIG. 5 is achieved. In this situation the bag has almostcompletely filled the cavity.

At this point a final air jet is fed to completely inflate the bag, asshown in FIG. 6. In this respect, the air surrounding the bag andtrapped between this latter and the walls defining the cavity is veryscarce. In the step shown in FIG. 6 the jet is maintained for a slightlylonger time than for the preceding steps. This enables the small amountof air remaining in the interspace to escape. FIG. 8 shows anenlargement of the situation prevailing in this step, and in the stepsshown in FIGS. 2 and 4. The bag is in contact with the wall defining thecavity of the container 5.

On termination of this latter step the jet is halted and the nozzle 20is extracted. The bag cools at this point and undergoes slight shrinkagedue to thermal contraction which causes it to separate in asubstantially uniform manner from the walls defining the containercavity.

FIG. 9 is an enlargement of a detail of FIG. 7. The situation hereinrepresented shows a uniform interspace 10 surrounding the entire bag,especially in the lateral region.

A bag inflation method has been described and illustrated comprisingthree inflation stages. Essentially three successive jets are fed,spaced apart by suitable pauses. This cycle lasts about 7 seconds for avessel of 30 ml.

More successive jets may be required, depending on the container and bagdimensions. Essentially, the air injection step and the subsequent jetinterruption to enable venting of the air situated in the interspaceoutside the bag can be repeated as many times as required.

However according to the present invention, at least one air ventingstep has to be provided, and hence at least one interruption in the airjet for inflating the bag.

Thus, at least two air jets should be necessary, spaced by at least apause or an interruption of the air jet.

It should be noted that the successive air jets fed into the bag canhave a constant pressure (for example 3 bar as indicated above), or canhave a pressure which varies depending on the current inflation step.For example the first jet fed into the bag can have a lower pressurethan the final maintaining jet, or vice versa. Consequently pressureregulation can be optimized, even with differences between one jet andthe next, to obtain maximum possible uniformity of bag thickness.

The bag formed in the container interior has a substantially uniformthickness, in contrast to that of the methods of the known art. The bagthickness is between 0.1 and 0.4 mm, preferably 0.2 mm, and isparticularly uniform, especially in the lateral (vertical) portion ofthe bag, i.e. that between the base and the top of the bag, where theneck is present.

Using the methods described in the known art, the bag would present alateral portion which is thinner towards the top, but thicker towardsthe bottom. This non-uniformity, due to the “stretching” caused in theinitial step by the nozzle, can result in bag tearing during inflationor during its filling with the product to be dispensed.

Moreover in the present solution the bag is detached from the walls ofthe container cavity, in the sense that an interspace exists which issubstantially uniform at least between the lateral wall of the bag andthe cavity walls, which facilitates air passage during the use of thepump. Moreover there are no regions or portions in which the bag adheresto the cavity wall. This is ensured by the “pulse” inflation methodwhich enables the bag to separate (possibly due to the bag/preformtemperature) by shrinkage and by the effect of the air trapped withinthe interspace by the bag inflation.

To complete the description, it should be noted that the user receivingthe container 5 with the bag 9 already inserted and retained in itintroduces into the bag (through the aperture in its neck 2) the desiredquantity of fluid substance, which can fill the bag as far as its neck2. The said user then inserts into the bag 9, through the aperture inits neck, a manually operable pump having a dispensing stem (whichprojects to the outside of the bag 9 and of the container 5) and a diptube which is immersed in the fluid substance contained in the bag.

The pump P is then locked securely onto the neck 6 of the container inknown manner, for example by a ring cap N having an internal threadwhich is screwed onto threads or helical ribs 6A projecting from theoutside of the container neck 6.

The ring cap N rests on the upper surface of a collar which projectsradially from the pump body and presses it into sealed contact with theflange 3 of the neck 2 of the bag 9, hence pressing the lower part ofthe pump into the cavity of the bag neck 2 where it forms a seal, thisseal being further improved by an elastic ring positioned immediatelybelow the collar.

The container 5 can evidently be made of any rigid material (in additionto glass), for example aluminium or other metal.

In all cases, for correct pump operation it is important that theinterspace 10 be in contact with the external environment, for examplevia the described passages formed between the container neck and the bagneck, below the flange.

One or more holes for air passage can however be provided in thecontainer, as illustrated in U.S. Pat. No. 3,420,413 and U.S.2004/0112921 A1, in any position therein.

Advantageously, the bag presents means (i.e. the flange 3) forconnection to a ring cap for fixing said pump to said container. Thesemeans, for example, engage the ring cap thread and enable the bag to beextracted from the body 5 during removal of the ring cap (and hence ofthe pump) from the container.

1. A container production method, comprising the steps of: a. providingan external rigid body (5) having a neck (6) defining an aperture givingaccess to the body cavity, b. and a preform formed of thermoplasticmaterial, the preform comprising a neck (2) from which a flange (3)radially extends, c. heating said preform above the softening point ofthe thermoplastic material, d. arranging the preform in the aperture ofthe body (5), e. feeding into the preform interior a first air jet whichinflates the preform to form a bag which at least partially occupiessaid body cavity, the walls of said bag being urged into contact withthe walls defining said cavity, f. interrupting said first jet such asto enable said thermoplastic material to shrink, with its consequentdetachment from the container walls, to hence allow outflow of the aircompressed by the bag expansion and trapped between the bag and thewalls defining said cavity, g. blowing into the bag a final air jet,said final air jet completely inflating the bag such as to cause it tocome into contact substantially with every point of at least the innerlateral surface of the cavity, and h. interrupting the air jet to hencefacilitate slight shrinkage of the bag which thus at least partiallyseparates from the cavity walls.
 2. A method as claimed in the precedingclaim, wherein after interrupting the initial air jet and while awaitingbag shrinkage, a further air jet is fed into the preform interior tofurther inflate it such that it occupies said body cavity to an evengreater extent, the walls of said bag also being in this case urged intocontact with the walls defining said cavity, then interrupting saidfurther jet to enable said thermoplastic material to shrink, with itsconsequent detachment from the container walls, to hence enable afurther outflow of the air compressed by the bag expansion and trappedbetween the bag and the walls defining said cavity.
 3. A method asclaimed in the preceding claim, wherein the steps described in claim 2are repeated until the bag almost completely occupies said cavity duringjet feed.
 4. A method as claimed in one or more of the preceding claims,wherein said air jet is interrupted after a time between 0.3 and 3seconds.
 5. A method as claimed in one or more of the preceding claims,wherein said air jet has a pressure between 2 and 6 bar.
 6. A method asclaimed in one or more of the preceding claims, wherein the preform isheated to a temperature between 100° C. and 150° C.
 7. A containercomprising a rigid body (5) having a neck (6) defining an apertureproviding access to the container cavity, and a bag (9) positioned inthe interior of the body (5), the bag being formed of thermoplasticmaterial and itself having a neck (2) from which there radially extendsa flange (3) which rests on a free edge of the neck (6) of the body (5)and defines a hole for providing access to the cavity of the bag (9) andfor sealedly housing the body of a hermetic pump (P) operable manuallyto withdraw the fluid substance (F) from the bag and feed it to theoutside through its dispensing stem (S), the bag being formed by hotblow moulding of a preform positioned directly within the container,characterised in that said bag has a substantially uniform thickness andis detached from the container along its entire outer surface.
 8. Acontainer as claimed in the preceding claim, wherein the substantiallyuniform thickness of the bag is between 0.1 and 0.4 mm.
 9. A containeror method as claimed in one or more of the preceding claims, wherein therigid body is formed of transparent material.
 10. A container or methodas claimed in one or more of the preceding claims, wherein the rigidbody is formed of glass.
 11. A container or method as claimed in one ormore of the preceding claims, wherein the preform/bag is formed of PETand/or PE and/or PP and/or by co-injection moulding various layers. 12.A container as claimed in one or more of the preceding claims, whereinsaid bag presents means for its connection to a ring nut for fixing saidpump to said container, said connection means being such as to enablethe bag to be extracted from the body (5) during the removal of the ringnut from the container.